Malicious peer identification for database block sequence

ABSTRACT

An example operation may include one or more of receiving, by each of one or more peripheral peers of a blockchain network, a sequence of new blocks from an orderer peer, calculating hashes for the sequence of new blocks, adding the hashes to a merkle tree, determining the merkle tree is different than merkle trees from a majority of peripheral peers, determining that one or more blocks that correspond to the different merkle trees from the majority of peripheral peers are different from the sequence of new blocks, and in response ceasing committing blocks to the blockchain network.

TECHNICAL FIELD

This application generally relates to methods and systems for detectingmalicious orderer or peripheral peers, and more particularly, tomalicious peer identification for database block sequences.

BACKGROUND

A centralized database stores and maintains data in a single database(e.g., a database server) at one location. This location is often acentral computer, for example, a desktop central processing unit (CPU),a server CPU, or a mainframe computer. Information stored on acentralized database is typically accessible from multiple differentpoints. Multiple users or client workstations can work simultaneously onthe centralized database, for example, based on a client/serverconfiguration. A centralized database is easy to manage, maintain, andcontrol, especially for purposes of security because of its singlelocation. Within a centralized database, data redundancy is minimized asa single storing place of all data also implies that a given set of dataonly has one primary record.

However, a centralized database suffers from significant drawbacks. Forexample, a centralized database has a single point of failure. Inparticular, if there are no fault-tolerance considerations and ahardware failure occurs (for example a hardware, firmware, and/or asoftware failure), all data within the database is lost and work of allusers is interrupted. In addition, centralized databases are highlydependent on network connectivity. As a result, the slower theconnection, the amount of time needed for each database access isincreased. Another drawback is the occurrence of bottlenecks when acentralized database experiences high traffic due to a single location.Furthermore, a centralized database provides limited access to databecause only one copy of the data is maintained by the database. As aresult, multiple devices cannot access the same piece of data at thesame time without creating significant problems or risk overwritingstored data. Furthermore, because a database storage system has minimalto no data redundancy, data that is unexpectedly lost is very difficultto retrieve other than through manual operation from back-up storage. Assuch, what is needed is a solution that overcomes these drawbacks andlimitations.

SUMMARY

One example embodiment provides a system that includes a blockchainnetwork, comprising one or more of an orderer peer, configured to createand propagate a sequence of new blocks, and one or more peripheralpeers, coupled to the orderer peer, each configured to perform one ormore of calculate hashes for the sequence of new blocks, add the hashesto a merkle tree, determine the merkle tree is different than merkletrees from a majority of peripheral peers, determine that one or moreblocks that correspond to the different merkle trees from the majorityof peripheral peers are different from the sequence of new blocks, andin response cease committing blocks to the blockchain network.

Another example embodiment provides a method that includes one or moreof receiving, by each of one or more peripheral peers of a blockchainnetwork, a sequence of new blocks from an orderer peer, calculatinghashes for the sequence of new blocks, adding the hashes to a merkletree, determining the merkle tree is different than merkle trees from amajority of peripheral peers, determining that one or more blocks thatcorrespond to the different merkle trees from the majority of peripheralpeers are different from the sequence of new blocks, and in responseceasing committing blocks to the blockchain network.

A further example embodiment provides a non-transitory computer readablemedium comprising instructions, that when read by a processor, cause theprocessor to perform one or more of receiving, by each of one or moreperipheral peers of a blockchain network, a sequence of new blocks froman orderer peer, calculating hashes for the sequence of new blocks,adding the hashes to a merkle tree, determining the merkle tree isdifferent than merkle trees from a majority of peripheral peers,determining that one or more blocks that correspond to the differentmerkle trees from the majority of peripheral peers are different fromthe sequence of new blocks, and in response ceasing committing blocks tothe blockchain network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a block diagram of a system for processing a newblock, according to example embodiments.

FIG. 1B illustrates a block diagram of a system for processing a newblock sequence, according to example embodiments.

FIG. 2A illustrates an example blockchain architecture configuration,according to example embodiments.

FIG. 2B illustrates a blockchain transactional flow, according toexample embodiments.

FIG. 3A illustrates a permissioned network, according to exampleembodiments.

FIG. 3B illustrates another permissioned network, according to exampleembodiments.

FIG. 3C illustrates a permissionless network, according to exampleembodiments.

FIG. 4 illustrates a system messaging diagram for performing blockintegrity checking, according to example embodiments.

FIG. 5A illustrates a flow diagram of an example method of verifying anew block in a blockchain, according to example embodiments.

FIG. 5B illustrates a flow diagram of an example method of verifying asequence of blocks in a blockchain, according to example embodiments.

FIG. 5C illustrates a flow diagram of an example method of preventingvulnerabilities in a blockchain, according to example embodiments.

FIG. 6A illustrates an example system configured to perform one or moreoperations described herein, according to example embodiments.

FIG. 6B illustrates another example system configured to perform one ormore operations described herein, according to example embodiments.

FIG. 6C illustrates a further example system configured to utilize asmart contract, according to example embodiments.

FIG. 6D illustrates yet another example system configured to utilize ablockchain, according to example embodiments.

FIG. 7A illustrates a process for a new block being added to adistributed ledger, according to example embodiments.

FIG. 7B illustrates contents of a new data block, according to exampleembodiments.

FIG. 7C illustrates a blockchain for digital content, according toexample embodiments.

FIG. 7D illustrates a block which may represent the structure of blocksin the blockchain, according to example embodiments.

FIG. 8A illustrates an example blockchain which stores machine learning(artificial intelligence) data, according to example embodiments.

FIG. 8B illustrates an example quantum-secure blockchain, according toexample embodiments.

FIG. 9 illustrates an example system that supports one or more of theexample embodiments.

DETAILED DESCRIPTION

It will be readily understood that the instant components, as generallydescribed and illustrated in the figures herein, may be arranged anddesigned in a wide variety of different configurations. Thus, thefollowing detailed description of the embodiments of at least one of amethod, apparatus, non-transitory computer readable medium and system,as represented in the attached figures, is not intended to limit thescope of the application as claimed but is merely representative ofselected embodiments.

The instant features, structures, or characteristics as describedthroughout this specification may be combined or removed in any suitablemanner in one or more embodiments. For example, the usage of the phrases“example embodiments”, “some embodiments”, or other similar language,throughout this specification refers to the fact that a particularfeature, structure, or characteristic described in connection with theembodiment may be included in at least one embodiment. Thus, appearancesof the phrases “example embodiments”, “in some embodiments”, “in otherembodiments”, or other similar language, throughout this specificationdo not necessarily all refer to the same group of embodiments, and thedescribed features, structures, or characteristics may be combined orremoved in any suitable manner in one or more embodiments. Further, inthe diagrams, any connection between elements can permit one-way and/ortwo-way communication even if the depicted connection is a one-way ortwo-way arrow. Also, any device depicted in the drawings can be adifferent device. For example, if a mobile device is shown sendinginformation, a wired device could also be used to send the information.

In addition, while the term “message” may have been used in thedescription of embodiments, the application may be applied to many typesof networks and data. Furthermore, while certain types of connections,messages, and signaling may be depicted in exemplary embodiments, theapplication is not limited to a certain type of connection, message, andsignaling.

Example embodiments provide methods, systems, components, non-transitorycomputer readable media, devices, and/or networks, which providemalicious peer identification for database block sequences.

In one embodiment the application utilizes a decentralized database(such as a blockchain) that is a distributed storage system, whichincludes multiple nodes that communicate with each other. Thedecentralized database includes an append-only immutable data structureresembling a distributed ledger capable of maintaining records betweenmutually untrusted parties. The untrusted parties are referred to hereinas peers or peer nodes. Each peer maintains a copy of the databaserecords and no single peer can modify the database records without aconsensus being reached among the distributed peers. For example, thepeers may execute a consensus protocol to validate blockchain storagetransactions, group the storage transactions into blocks, and build ahash chain over the blocks. This process forms the ledger by orderingthe storage transactions, as is necessary, for consistency. In variousembodiments, a permissioned and/or a permissionless blockchain can beused. In a public or permission-less blockchain, anyone can participatewithout a specific identity. Public blockchains can involve nativecryptocurrency and use consensus based on various protocols such asProof of Work (PoW). On the other hand, a permissioned blockchaindatabase provides secure interactions among a group of entities whichshare a common goal but which do not fully trust one another, such asbusinesses that exchange funds, goods, information, and the like.

This application can utilize a blockchain that operates arbitrary,programmable logic, tailored to a decentralized storage scheme andreferred to as “smart contracts” or “chaincodes.” In some cases,specialized chaincodes may exist for management functions and parameterswhich are referred to as system chaincode. The application can furtherutilize smart contracts that are trusted distributed applications whichleverage tamper-proof properties of the blockchain database and anunderlying agreement between nodes, which is referred to as anendorsement or endorsement policy. Blockchain transactions associatedwith this application can be “endorsed” before being committed to theblockchain while transactions, which are not endorsed, are disregarded.An endorsement policy allows chaincode to specify endorsers for atransaction in the form of a set of peer nodes that are necessary forendorsement. When a client sends the transaction to the peers specifiedin the endorsement policy, the transaction is executed to validate thetransaction. After validation, the transactions enter an ordering phasein which a consensus protocol is used to produce an ordered sequence ofendorsed transactions grouped into blocks.

This application can utilize nodes that are the communication entitiesof the blockchain system. A “node” may perform a logical function in thesense that multiple nodes of different types can run on the samephysical server. Nodes are grouped in trust domains and are associatedwith logical entities that control them in various ways. Nodes mayinclude different types, such as a client or submitting-client nodewhich submits a transaction-invocation to an endorser (e.g., peer), andbroadcasts transaction-proposals to an ordering service (e.g., orderingnode). Another type of node is a peer node which can receive clientsubmitted transactions, commit the transactions and maintain a state anda copy of the ledger of blockchain transactions. Peers can also have therole of an endorser, although it is not a requirement. Anordering-service-node or orderer is a node running the communicationservice for all nodes, and which implements a delivery guarantee, suchas a broadcast to each of the peer nodes in the system when committingtransactions and modifying a world state of the blockchain, which isanother name for the initial blockchain transaction which normallyincludes control and setup information.

This application can utilize a ledger that is a sequenced,tamper-resistant record of all state transitions of a blockchain. Statetransitions may result from chaincode invocations (i.e., transactions)submitted by participating parties (e.g., client nodes, ordering nodes,endorser nodes, peer nodes, etc.). Each participating party (such as apeer node) can maintain a copy of the ledger. A transaction may resultin a set of asset key-value pairs being committed to the ledger as oneor more operands, such as creates, updates, deletes, and the like. Theledger includes a blockchain (also referred to as a chain) which is usedto store an immutable, sequenced record in blocks. The ledger alsoincludes a state database which maintains a current state of theblockchain.

This application can utilize a chain that is a transaction log which isstructured as hash-linked blocks, and each block contains a sequence ofN transactions where N is equal to or greater than one. The block headerincludes a hash of the block's transactions, as well as a hash of theprior block's header. In this way, all transactions on the ledger may besequenced and cryptographically linked together. Accordingly, it is notpossible to tamper with the ledger data without breaking the hash links.A hash of a most recently added blockchain block represents everytransaction on the chain that has come before it, making it possible toensure that all peer nodes are in a consistent and trusted state. Thechain may be stored on a peer node file system (i.e., local, attachedstorage, cloud, etc.), efficiently supporting the append-only nature ofthe blockchain workload.

The current state of the immutable ledger represents the latest valuesfor all keys that are included in the chain transaction log. Since thecurrent state represents the latest key values known to a channel, it issometimes referred to as a world state. Chaincode invocations executetransactions against the current state data of the ledger. To make thesechaincode interactions efficient, the latest values of the keys may bestored in a state database. The state database may be simply an indexedview into the chain's transaction log, it can therefore be regeneratedfrom the chain at any time. The state database may automatically berecovered (or generated if needed) upon peer node startup, and beforetransactions are accepted.

Some benefits of the instant solutions described and depicted hereininclude a novel ability to detect a malicious orderer peer or peripheralpeer in a permissioned blockchain network, and a batch process to detectmalicious behavior over a group of sequentially consecutive blocks.

It is not possible for the disclosed processes to be implemented on atraditional database instead of a blockchain, because the presentprocesses utilize distributed consensus for new block commitment andshared ledgers to store committed blocks. Traditional databases lackthese processes and structures.

The present application creates a functional improvement to computerfunctionality utilizing the blockchain by detecting a peer that may beacting maliciously to corrupt data or store modified data within ablockchain network. Although permissioned blockchain networks aresometimes thought of as inherently secure, it is still possible forcorrupted blocks to be stored to a blockchain during the commitmentphase. By detecting corrupted or changed blocks. Network security andintegrity is preserved. No new data is stored in blocks of a blockchain.

In a blockchain network, each peer includes a shared ledger, whichincludes an ordered sequence of transactions that are usually groupedinto blocks for efficient dissemination. In some permissioned blockchainnetworks, there are a set of peers dedicated to order and batch thetransactions into blocks (hereafter “ordering peers” or “orderers”) anddistribute them to the remaining peers (hereafter “peripheral peers”) ofthe blockchain network. The distribution is done by having theperipheral peers pull the blocks from the ordering peers, having theordering peers send the blocks to the peripheral peers, by an approachthat involves one of both the previous approaches, or by an approachthat involves a previous approach, but also by having the peripheralpeers send each other the blocks and not receiving them directly fromthe ordering peers.

In most blockchain networks, the transactions sent by the blockchainnetwork participants are signed with asymmetric cryptography, such as(but not limited to) RSA or ECDSA signature schemes. Since the orderingpeers lack private keys, they cannot mutate the transactions sent to beordered while preserving the validity of the signature, because thatrequires significant computational power.

A threat model to permissioned blockchain networks may consider eithermalicious ordering peers or malicious peripheral peers. Maliciousordering peers may collude with other ordering peers, present differentblocks to peripheral peers, and even collude with peripheral peers(depending on their threat model) on altering their protocol. There isnot an upper bound on the percentage of malicious ordering peers.Peripheral peers may be considered honest if they cooperate fully withother peripheral peers, and adhere to the protocols. Peripheral peersmay be considered malicious if they may run a modified version of theprotocol and attempt to prevent honest peers from discovering that theydo not conform to the protocol the honest peers execute.

In Hyperledger Fabric v0.6, the architecture was built around a smallcore of validator peers connected in a full mesh topology which executeda byzantine consensus protocol (i.e PBFT), and all peers periodicallyexchanged block hashes via a checkpoint mechanism. The validator peerscould use these hashes if they collected f+1 identical hashes of a givensequence number to safely synchronize their own ledger from other peersthat published the corresponding hashes after doing backward hash chainvalidation to ensure the integrity of the block sequence fetched fromremote validator peers.

The assumption in Hyperledger Fabric v0.6 was that f is a complete upperbound on the number of byzantine validator peers, so if a validator nodereceived f+1 attestations of the same hash for a given block sequence,it will not reach a forked world state. However, Hyperledger Fabric'sv0.6 architecture is fundamentally different than the architecture thepresent application describes, namely it is a homogenous one and as suchit doesn't fit use cases in which there are many peers deployed around acentral core of peers which cuts the blocks. In such a layout, theperipheral peers cannot use the mechanism implemented in HyperledgerFabric v0.6 as a black box, since even if there is an upper bound on thepercentage of the malicious peripheral peers, collecting f+1attestations of the same block hash M means nothing because since theblocks aren't cut by peripheral peers, there could be a different groupof f+1 peripheral peers which collected attestations on a differentblock hash H_(j)≠H_(i) and thus a chain fork would occur withoutdetection. Additionally, if the Hyperledger Fabric v0.6 mechanism wouldhave been used by the peripheral peers, a fork could still occur withoutearly detection. The Hyperledger Fabric v0.6 protocol and implementationdid not relay information transitively between peers but had apoint-to-point dissemination only. Thus, it is not practical in largescale deployments, while the present application suggests the use of agossip protocol combined with signed messages. This allows propagatingdata in an efficient and scalable manner and adds an ability to detectand expose peripheral peers which voted for two different hashes, andthus disincentivizes such behavior.

The goal of the present application is to detect forking attacks, evenif all ordering peers are malicious, as long as they don't coerce theperipheral peers into adopting different blocks. While the orderingpeers cannot mutate the transactions that would appear in the blocks(since they lack the private keys of the transaction submitters), theycan still harm the integrity of the blockchain by causing chain forks bysending different blocks to different peripheral peers. This maysabotage client applications that read the transactions in the sharedledger by making different clients see a divergent view of theblockchain data.

With a crash fault tolerant (CFT) ordering service, the ability todetect state divergence is a very critical and important property. Itmay allow publishing an alerting event for an external monitoringsystem. Moreover, byzantine fault tolerant (BFT) ordering services maymitigate the risk of the chain fork since there may be no guarantee of anumber of adversarial ordering service peer growth beyond a threshold ofone third of total ordering service network size.

The disclosure herein introduces methods for detecting attempts of achain fork by peers of the blockchain network 100, under severalassumptions.

First, the blocks created by the non-malicious (honest) ordering peerseach have a monotonically increasing and successive sequence. The firstblock is sequenced 0, the next one created is sequenced 1, and so forth.By not creating a block of a specific sequence, a malicious orderingnode cannot create a chain fork, because it is equivalent to an honestordering node that has a crash failure and then recovers. Second, theordering peers cryptographically sign the blocks they output to thenetwork and each block carries with it an identifier of the node such as(but not limited to) an x509 certificate. The signature may be verifiedusing the identifier, and the identifier itself can be verified by someidentity infrastructure such as (but not limited to) a certificateauthority validation chain starting at the identifier of the node andending at a certificate authority that the verifier node trusts.

Third, the peripheral peers may all use the same cryptographic hashfunction H.

FIG. 1A illustrates a block diagram of a system for processing a newblock, according to example embodiments. Referring to FIG. 1A, thenetwork 100 includes an orderer peer 104, a peripheral peer 108, otherperipheral peers 112, and a shared ledger 128. The network 100 is apermissioned blockchain network, such as a Hyperledger Fabric blockchainnetwork.

The protocol herein uses thresholds of a total node count of theblockchain network 100, which implies that the peers are countable andhow many peers there are is a known number. In a public blockchainnetwork such as bitcoin, the number of nodes there are is never known,and a threshold on the percentage of byzantine nodes (denoted herein asf) doesn't exist because a malicious party can join as many nodes as itwants into the blockchain network by generating identities for itsnodes, and run more than f nodes on its own.

The orderer peer 104 receives endorsed blockchain transactions fromother peers within blockchain network 100 and gathers groups oftransactions into new blocks 116. Although one orderer peer 104 isillustrated, it should be understood there may be any number of ordererpeers 104 in the blockchain network 100. One orderer peer 104 is shownin order to simplify the description of the network 100 and aid inunderstanding of the disclosed processes. When the orderer peer 104creates a new block 116, it transfers the new block 116 to peripheralpeers 108, 112 of the blockchain network 100. Peripheral peers 108, 112are all other peers of the blockchain network 100 that are not ordererpeers 104, and may be generally considered to be blockchain peers.

In the disclosed processes, all peripheral peers 108, 112 of the network100 operate the disclosed processes in parallel. However, thedescription and processes focus on what happens within an individualperipheral peer (peripheral peer 108) and how it cooperates with theother peripheral peers 112 in the network. It should therefore beunderstood that the operations discussed with respect to peripheral peer108 are at the same time occurring in each of peripheral peers 112.There may be any number of peripheral peers 108, 112 in the blockchainnetwork 100.

In response to receiving the new block 116, the peripheral peer 108calculates a hash 120 of the new block 116. At the same time, theperipheral peer 108 requests hashes of the new block 116 from a majorityof the peripheral peers 112 in the blockchain network 100. Each of theother peripheral peers 112 do the same. The peripheral peer 108 receivesthe requested hashes 128 from the majority of other peripheral peers112, and compares the requested hashes 128 to the calculated hash 120.If all of the requested hashes 128 are the same as the calculated hash120, then the new block 116 is valid and the peripheral peer 108includes the new block as a committed block 136 stored to a sharedledger 132 of the blockchain network 100. If one or more of therequested hashes 128 are not the same as the calculated hash 120, thenmost likely the orderer peer 104 that created the new block 116 ispossibly malicious.

The peripheral peer 108 next verifies whether the orderer peer 104 ismalicious by requesting the new block from each of the peripheral peers112 that provided a requested hash 128 that miscompared with thecalculated hash 120. Those peripheral peers 112 provide the requestedblock 124 to the peripheral peer 108, who then compares the requestedblock 124 to the new block 116 the peripheral peer 108 received. If therequested blocks 124 are not the same as the new block 116, then theorderer peer 104 that created the new block 116 is a malicious ordererpeer 104.

Honest peripheral peers 108, 112 (that do not participate in theordering of the transactions) have no incentive to lie to each aboutblocks they receive from the ordering peers 104, because it is ofinterest to the peripheral peers 108, 112 to have the same shared ledger132 contents since they do not collude with the ordering peers 104.Also, each peer could be asked to prove its assertion about a block bysending the block itself, and thus exposing its lie since the block issigned by the ordering node(s) 104. Therefore, in any environment inwhich the peripheral peers 108, 112 can lie about the blocks theyreceive from the ordering peers 104, a separate protocol that requests aproof by receiving these blocks from peripheral peers 108, 112 may berun alongside the protocol outlined herein. In the case of maliciousperipheral peers 108, 112, they may lie to honest peers and possiblycollude with the ordering peers 104 or other peripheral peers 108, 112to cause different honest peers to adopt blocks that contain differenttransactions or blocks with the same transactions but in differentorder. It is considered acceptable that malicious peers adopt differentblocks than honest peers, but all honest peers must adopt the sameblocks.

The number of malicious peripheral peers 108, 112 in the blockchainnetwork cannot exceed a certain (publicly known) percentage of totalperipheral peers. Specifically, an upper bound on the number of possiblemalicious peripheral peers 108, 112 in the network is known and isdenoted herein as f. The peripheral peers 108, 112 all share a commonnumber B that is known to everyone in the blockchain network 100. Peersarrange blocks received from the ordering peers 104 in batches of sizeB. If a peer has not received a block but did receive a block b_(j) forsome j>i, it is guaranteed to receive b_(i) eventually from either anordering peer 104 or a peripheral peer 108, 112. In addition, theperipheral peers 108, 112 all share a common duration of time T_(out)that is known to all entities within the blockchain network 100.

Data structures of the present application may reside in memory or on adisk or on any type of storage or a mix of storage devices. Theperipheral peers 108, 112 all maintain the blocks in a successive andcontinuous ordered list of blocks starting from 0 up to the latest blockreceived. A hash of the blocks of the list are used as leaves in amerkle tree 154, and each time a block is received and validated, themerkle tree 154 is reconstructed and recomputed at each peripheral peer108, 112. The peripheral peers 108, 112 continually notify each other oftheir latest validated and non-validated block sequences. A validatedblock is considered a block that has been stored to the shared ledger132 and is a leaf in the merkle tree 154, and a non-validated block isone that is not. Since blocks enter the shared ledger 132 in-order, ifb_(j) is a validated block, then ∀i∈{0 . . . j}: b_(i) is alsovalidated.

Peers consult with a threshold count (hereafter t) of other peripheralpeers 108, 112 in order to withstand scenarios in which either anordering peer 104 publishes different blocks to different peers, ormalicious peripheral peers 108, 112 (if applicable) do not conform totheir protocol in order to cause honest peers to adopt divergent sets ofblocks. The threshold count t that a peer needs to consult with dependson the threat model. For honest peripheral peers 108, 112, the thresholdcount t may include at least 50% of the total peripheral peers 108, 112out of all peripheral peers 108, 112, which means that including thepeer itself, is at least 50%+1. For malicious peripheral peers 108, 112:(reminder: the upper bound on the malicious peer count is denoted asf=at least 50%+f of the total peripheral peer 108, 112 count out of allperipheral peers 108, 112, which means that including the peer itself,is at least 50%+f+1. Peers do not need to directly communicate with eachother to collect a threshold count of hashes, but can also sign the datathey want to publish and propagate this among the peripheral peers 108,112 in a dissemination protocol such as (but not limited to) gossip,broadcast, etc.

As described previously, peers arrange blocks received from the orderingservice in batches of size B. If a peer hasn't received a block b_(i)but did receive a block b_(j) for some j>t, it is guaranteed to receiveb_(i) eventually from either an ordering peer 104 or a peripheral peer108, 112. It follows from here that if a peer received all blocks in abatch of blocks b_(i−B), b_(I−B+1), . . . b_((i+1)·B−1) but a set ofblocks b_(j), . . . b_(j+k) s·tj+k<(i+1)·B−1, it will obtain the missingblocks eventually.

However, if there is a consecutive set of indices that the last of themis (i+1)·B−1 that are missing, there is (obviously) no guarantee thatthe peer would receive them at all, since it may be that this is thelast batch that is being received, and no new blocks have been createdby any ordering peer 104. In this case, then T_(out) denotes the timelimit a peer would wait until it would decide to perform step (2) of theprotocol.

The protocol itself is described algorithmically as follows:

-   -   1. On reception of B blocks b_(i), b_(i+1), . . . b_(i+B−1) by        peripheral peer p: Consult t peripheral peers (denote the set of        peers Q) of their non-validated block sequences and validated        block sequences.        -   a. If t peers with a validated sequence of blocks b′_(i),            b′_(i+1), . . . b′_(i+B−1), weren't found, retrieve from t            peers the hashes H(b_(i)), H(b_(i+1)), . . . H(b_(i+B−1))            that they have received, if applicable.            -   If ∃j∈[t, . . . t+B−1]s·t H(b_(j))≠H(b′_(j)), a fork has                been detected.            -   If such t hashes haven't been collected—go back to step                (1).        -   b. As explained, if there is a node q∈Q with a sequence of            blocks b it means it has constructed a merkle tree that            includes these blocks in its lowest level (leaf level).            -   Obtain from e the root hash R_(B) ^(q) of a merkle tree                that its leaves are the hashes H(b_(i)), H(b_(i+1)), . .                . H(b_(i+B−1)) (as explained, q maintains such a merkle                tree, and since r_(B) solely depends on b_(i), b_(i+1),                . . . b_(i+B−1), it will stay the same no matter what is                q's ledger height)        -   c. Construct a temporary merkle tree that its leaves are            b_(i), b_(i+1), . . . b_(i+B−1) and its root is r_(B), and            compare it with r_(B) ^(q)∀q∈Q            -   i. If ∃q∈Q s·t r_(B)≠r_(B) ^(q), it means there is some                block b_(j) s·ti≤j≤i+B−1 in p that is different than the                blocks in q, and thus                -   a chain fork has been successfully detected.            -   ii. Else, consider b_(i), b_(i+1), . . . b_(i+B−1)                validated, commit them to the shared ledger, and update                the merkle tree.    -   2. If B blocks aren't received from the blockchain network 100        within a timely manner T_(out):        -   a. Let b_(i), b_(i+1), . . . b_(i+k), s·t k<B−1 be the last            blocks received from the blockchain network 100.        -   b. Define blocks z_(i+k+1), . . . z_(i+B−1) as blocks that            are missing from the last batch, and denote their hashes as            0.        -   c. Perform the protocol of step (1) with the blocks while            consulting t peripheral peers with the blocks b_(i),            b_(i+1), . . . b_(i+k), z_(i+k+1), . . . z_(i+B−1), but when            contacting the other peers—specify the indices i+k, . . .            i+B−1 in case the contacted peer q has received new blocks            at the time of the query.

Note: Step 1 may also be performed by sending a merkle tree root whichits leaves are the hashes of the blocks locks b′_(i), b′_(i+1), . . .b′_(i+B−1), but for simplicity and easy distinguishability betweenvalidated blocks that are committed and have a merkle tree built forthem and non-validated blocks, the protocol doesn't use a merkle treefor step 1a. Also, a merkle tree method may be replaced with acumulative hashing that is defined in the following way:H(H(b_(i))∥H(b_(i+1)) . . . ∥H(b_(B+i−1))) or by a similar method.

As peripheral peers consult each other about their block hashes, theycan either adopt their block hashes, or detect a chain forking attempt.The blocks may be modeled as values that peripheral peers input into theprotocol and the output is either the blocks they propose or an event ofa forking attempt.

The disclosed protocol fulfills the properties of abortable consensus.

Uniform validity teaches: “If a process decides v then some processpreviously proposed v”. Therefore, if a peripheral peer adopts a certainblock, it means that there are t other peripheral peers that alsoproposed that block either in the past (it was validated) or in thecurrent round (the block wasn't validated before by any peripheralpeer).

Agreement teaches: “Correct processes do not decide different values”.Therefore, assume in contradiction that there are 2 peripheral peers pand q such that p adopted block b_(i) with hash H_(p) and q adoptedblock b_(i) with hash H_(q). Since every peripheral peer consults withat least 50%+f other peripheral peers, there is an honest peripheralpeer r that both p and q consulted with. From the assumption and theprotocol, it follows that r communicated q its hash of b_(i) is H_(q)and communicated pits hash of b_(i) is H_(p). Therefore, r doesn'tconform to the protocol and hence is malicious, which indicates acontradiction.

Termination teaches: “Eventually all correct processes either decide orabort”. It may be easily derived from the protocol, that for each blocka peripheral peer consults with other peers about, it is either informedabout only the hash it computed for the block itself, or is informedabout a different hash and then it aborts the protocol because a chainsplit attempt was detected.

α—Abortability teaches: “There exists an α<1 such that for any failurepattern in which most of processes are correct, the probability thatthere exists some process that aborts in a run with the failure patternis at most α”. Denote the number of peripheral peers as n and the amountof malicious peripheral peers as f, such that 2f<n. Let p be aperipheral peer. For simplicity of calculation, assume that it consultswith exactly (instead of at least) n/2+f other peripheral peers aboutthe blocks it possesses. The probability of selecting only honestperipheral peers is:

     Phone?, ?indicates text missing or illegible when filed

and since every peripheral peer selects independently, the probabilityof all honest peripheral peers do not select any malicious peripheralpeer for a given block batch is: (p_(honest))^(n−f), which means theprobability that some process aborts in a run is at most:α=1−(p_(honest))^(n−f)

FIG. 1B illustrates a block diagram of a system for processing a newblock sequence, according to example embodiments. Referring to FIG. 1B,the network 150 includes the same peers 104, 108, 112 and shared ledger132 described with respect to FIG. 1A, but represents a system 150 wherea sequence of blocks 170 are processes instead of a single block 116. Asequence of blocks 170 is a group of two or more consecutive blocks.

To make the protocol more efficient, network bandwidth should beconserved and the amount of data transferred should preferably beminimized. To that end, the blocks are arranged into batches of someglobally known batch size B, and for every such batch of blocks orsequence of blocks 170, a merkle tree 154 is created, where the leafnodes of the merkle tree 154 are the block hashes of the batch. In orderfor two peripheral peers 108, 112 to compare all hashes of the blocks inthe batch, it is only necessary to compare the root node hash 158 of themerkle tree 154. Assuming the hash function of the merkle tree iscollision resistant, all block hashes of the batch are the same if andonly if the merkle tree root hashes 158 in possession of the twoperipheral peers 108, 112 are equal. This saves network bandwidth and ismore efficient than comparing a block at a time as in FIG. 1A becausethe same merkle tree root node hash 158 may be sent to all theperipheral peers 108, 112 in the blockchain network 150.

However, there is a corner case that needs to be addressed: Since ablockchain increments blocks one by one, and not in batches, it may bethat too much time (denoted as T_(out) herein) has passed, yet theblockchain network 150 may not have enough blocks to fill in a batch ofB blocks. In such a case, the peripheral peers 108, 112 simply fill inthe remaining vacant places in the batch with hashes of zeros, compute amerkle tree root node hash 158, and send it to the peers along with theindices that were zeros instead of actual block hashes.

Each peripheral peer 108, 112 includes a merkle tree 154. The merkletree 154 includes leaf nodes that each store a hash for a block. Themerkle tree 154 has a root node, which stores a root node hash 158 forthe entire merkle tree 154. Thus, by comparing root node hashes 158, aperipheral peer 108, 112 may determine that two or more merkle trees 154are identical.

If the merkle trees 154 are constructed on hashes of blocks that havebeen validated (committed), then when receiving blocks that have notbeen validated—their hashes may be sent and consulted with peripheralpeers 108, 112 in the same manner as before. Otherwise, if the merkletrees 154 are constructed on hashes of blocks regardless of theirvalidation, then when receiving blocks that have not been validated, themerkle tree 154 needs to be constantly updated along with the merkletree 154. The peer sends also the range of the consecutive prefix ofblocks that are not zeros (in order for the other peripheral peer 108,112 to understand which leaves correspond to blocks that are notincluded in the merkle tree 154 construction).

In response to receiving the sequence of blocks 170, the peripheral peer108 adds the sequence of blocks 170 to its own merkle tree 154 bycalculating hashes for each block of the sequence of hashes 170 andstoring the calculated hashes to leaf nodes of its own merkle tree 154.At the same time, the peripheral peer 108 requests root node hashes 158from a majority of the peripheral peers 112 in the blockchain network100, of their own merkle tree 154. Recall that each peripheral peer 108,112 is executing the steps in parallel, including updating its ownmerkle tree 154 with hashes from the sequence of blocks 170. Theperipheral peer 108 receives the requested root node hashes 162 from themajority of other peripheral peers 112, and compares the requested rootnode hashes 128 to its own root node hash 158. If all of the requestedroot node hashes 162 are the same as the root node hash 158 of theperipheral peer 108, then the sequence of blocks 170 is valid and theperipheral peer 108 includes the sequence of blocks 170 as committedblocks 136 stored to the shared ledger 132 of the blockchain network100. If one or more of the requested root node hashes 162 are not thesame as the root node hash 158 of the peripheral peer 108, then mostlikely the orderer peer 104 that created the sequence of blocks 170 ispossibly malicious.

The peripheral peer 108 next verifies whether the orderer peer 104 ismalicious by requesting the sequence of blocks from each of theperipheral peers 112 that provided a requested root node hash 162 thatmiscompared with the root node hash 158 of the peripheral peer 108.Those peripheral peers 112 provide the requested sequence of blocks 166to the peripheral peer 108, who then compares the requested sequence ofblocks 166 to the sequence of blocks 170 the peripheral peer 108received. If the requested sequence of blocks 166 are not the same asthe sequence of blocks 170, then the orderer peer 104 that created thesequence of blocks 170 is a malicious orderer peer 104.

FIG. 2A illustrates a blockchain architecture configuration 200,according to example embodiments. Referring to FIG. 2A, the blockchainarchitecture 200 may include certain blockchain elements, for example, agroup of blockchain nodes 202. The blockchain nodes 202 may include oneor more nodes 204-210 (these four nodes are depicted by example only).These nodes participate in a number of activities, such as blockchaintransaction addition and validation process (consensus). One or more ofthe blockchain nodes 204-210 may endorse transactions based onendorsement policy and may provide an ordering service for allblockchain nodes in the architecture 200. A blockchain node may initiatea blockchain authentication and seek to write to a blockchain immutableledger stored in blockchain layer 216, a copy of which may also bestored on the underpinning physical infrastructure 214. The blockchainconfiguration may include one or more applications 224 which are linkedto application programming interfaces (APIs) 222 to access and executestored program/application code 220 (e.g., chaincode, smart contracts,etc.) which can be created according to a customized configurationsought by participants and can maintain their own state, control theirown assets, and receive external information. This can be deployed as atransaction and installed, via appending to the distributed ledger, onall blockchain nodes 204-210.

The blockchain base or platform 212 may include various layers ofblockchain data, services (e.g., cryptographic trust services, virtualexecution environment, etc.), and underpinning physical computerinfrastructure that may be used to receive and store new transactionsand provide access to auditors which are seeking to access data entries.The blockchain layer 216 may expose an interface that provides access tothe virtual execution environment necessary to process the program codeand engage the physical infrastructure 214. Cryptographic trust services218 may be used to verify transactions such as asset exchangetransactions and keep information private.

The blockchain architecture configuration of FIG. 2A may process andexecute program/application code 220 via one or more interfaces exposed,and services provided, by blockchain platform 212. The code 220 maycontrol blockchain assets. For example, the code 220 can store andtransfer data, and may be executed by nodes 204-210 in the form of asmart contract and associated chaincode with conditions or other codeelements subject to its execution. As a non-limiting example, smartcontracts may be created to execute reminders, updates, and/or othernotifications subject to the changes, updates, etc. The smart contractscan themselves be used to identify rules associated with authorizationand access requirements and usage of the ledger. For example, theinformation 226 may include a new block or a new block sequence from anorderer peer, and may be processed by one or more processing entities(e.g., virtual machines) included in the blockchain layer 216. Theresult 228 may include a request to other peripheral peers to providehashes and blocks in order to make comparisons to detect maliciousbehavior. The physical infrastructure 214 may be utilized to retrieveany of the data or information described herein.

A smart contract may be created via a high-level application andprogramming language, and then written to a block in the blockchain. Thesmart contract may include executable code which is registered, stored,and/or replicated with a blockchain (e.g., distributed network ofblockchain peers). A transaction is an execution of the smart contractcode which can be performed in response to conditions associated withthe smart contract being satisfied. The executing of the smart contractmay trigger a trusted modification(s) to a state of a digital blockchainledger. The modification(s) to the blockchain ledger caused by the smartcontract execution may be automatically replicated throughout thedistributed network of blockchain peers through one or more consensusprotocols.

The smart contract may write data to the blockchain in the format ofkey-value pairs. Furthermore, the smart contract code can read thevalues stored in a blockchain and use them in application operations.The smart contract code can write the output of various logic operationsinto the blockchain. The code may be used to create a temporary datastructure in a virtual machine or other computing platform. Data writtento the blockchain can be public and/or can be encrypted and maintainedas private. The temporary data that is used/generated by the smartcontract is held in memory by the supplied execution environment, thendeleted once the data needed for the blockchain is identified.

A chaincode may include the code interpretation of a smart contract,with additional features. As described herein, the chaincode may beprogram code deployed on a computing network, where it is executed andvalidated by chain validators together during a consensus process. Thechaincode receives a hash and retrieves from the blockchain a hashassociated with the data template created by use of a previously storedfeature extractor. If the hashes of the hash identifier and the hashcreated from the stored identifier template data match, then thechaincode sends an authorization key to the requested service. Thechaincode may write to the blockchain data associated with thecryptographic details.

FIG. 2B illustrates an example of a blockchain transactional flow 250between nodes of the blockchain in accordance with an exampleembodiment. Referring to FIG. 2B, the transaction flow may include atransaction proposal 291 sent by an application client node 260 to anendorsing peer node 281. The endorsing peer 281 may verify the clientsignature and execute a chaincode function to initiate the transaction.The output may include the chaincode results, a set of key/valueversions that were read in the chaincode (read set), and the set ofkeys/values that were written in chaincode (write set). The proposalresponse 292 is sent back to the client 260 along with an endorsementsignature, if approved. The client 260 assembles the endorsements into atransaction payload 293 and broadcasts it to an ordering service node284. The ordering service node 284 then delivers ordered transactions asblocks to all peers 281-283 on a channel. Before committal to theblockchain, each peer 281-283 may validate the transaction. For example,the peers may check the endorsement policy to ensure that the correctallotment of the specified peers have signed the results andauthenticated the signatures against the transaction payload 293.

Referring again to FIG. 2B, the client node 260 initiates thetransaction 291 by constructing and sending a request to the peer node281, which is an endorser. The client 260 may include an applicationleveraging a supported software development kit (SDK), which utilizes anavailable API to generate a transaction proposal. The proposal is arequest to invoke a chaincode function so that data can be read and/orwritten to the ledger (i.e., write new key value pairs for the assets).The SDK may serve as a shim to package the transaction proposal into aproperly architected format (e.g., protocol buffer over a remoteprocedure call (RPC)) and take the client's cryptographic credentials toproduce a unique signature for the transaction proposal.

In response, the endorsing peer node 281 may verify (a) that thetransaction proposal is well formed, (b) the transaction has not beensubmitted already in the past (replay-attack protection), (c) thesignature is valid, and (d) that the submitter (client 260, in theexample) is properly authorized to perform the proposed operation onthat channel. The endorsing peer node 281 may take the transactionproposal inputs as arguments to the invoked chaincode function. Thechaincode is then executed against a current state database to producetransaction results including a response value, read set, and write set.However, no updates are made to the ledger at this point. In 292, theset of values, along with the endorsing peer node's 281 signature ispassed back as a proposal response 292 to the SDK of the client 260which parses the payload for the application to consume.

In response, the application of the client 260 inspects/verifies theendorsing peers signatures and compares the proposal responses todetermine if the proposal response is the same. If the chaincode onlyqueried the ledger, the application would inspect the query response andwould typically not submit the transaction to the ordering node service284. If the client application intends to submit the transaction to theordering node service 284 to update the ledger, the applicationdetermines if the specified endorsement policy has been fulfilled beforesubmitting (i.e., did all peer nodes necessary for the transactionendorse the transaction). Here, the client may include only one ofmultiple parties to the transaction. In this case, each client may havetheir own endorsing node, and each endorsing node will need to endorsethe transaction. The architecture is such that even if an applicationselects not to inspect responses or otherwise forwards an unendorsedtransaction, the endorsement policy will still be enforced by peers andupheld at the commit validation phase.

After successful inspection, in step 293 the client 260 assemblesendorsements into a transaction and broadcasts the transaction proposaland response within a transaction message to the ordering node 284. Thetransaction may contain the read/write sets, the endorsing peerssignatures and a channel ID. The ordering node 284 does not need toinspect the entire content of a transaction in order to perform itsoperation, instead the ordering node 284 may simply receive transactionsfrom all channels in the network, order them chronologically by channel,and create blocks of transactions per channel.

The blocks of the transaction are delivered from the ordering node 284to all peer nodes 281-283 on the channel. The transactions 294 withinthe block are validated to ensure any endorsement policy is fulfilledand to ensure that there have been no changes to ledger state for readset variables since the read set was generated by the transactionexecution. Transactions in the block are tagged as being valid orinvalid. Furthermore, in step 295 each peer node 281-283 appends theblock to the channel's chain, and for each valid transaction the writesets are committed to current state database. An event is emitted, tonotify the client application that the transaction (invocation) has beenimmutably appended to the chain, as well as to notify whether thetransaction was validated or invalidated.

FIG. 3A illustrates an example of a permissioned blockchain network 300,which features a distributed, decentralized peer-to-peer architecture.In this example, a blockchain user 302 may initiate a transaction to thepermissioned blockchain 304. In this example, the transaction can be adeploy, invoke, or query, and may be issued through a client-sideapplication leveraging an SDK, directly through an API, etc. Networksmay provide access to a regulator 306, such as an auditor. A blockchainnetwork operator 308 manages member permissions, such as enrolling theregulator 306 as an “auditor” and the blockchain user 302 as a “client”.An auditor could be restricted only to querying the ledger whereas aclient could be authorized to deploy, invoke, and query certain types ofchaincode.

A blockchain developer 310 can write chaincode and client-sideapplications. The blockchain developer 310 can deploy chaincode directlyto the network through an interface. To include credentials from atraditional data source 312 in chaincode, the developer 310 could use anout-of-band connection to access the data. In this example, theblockchain user 302 connects to the permissioned blockchain 304 througha peer node 314. Before proceeding with any transactions, the peer node314 retrieves the user's enrollment and transaction certificates from acertificate authority 316, which manages user roles and permissions. Insome cases, blockchain users must possess these digital certificates inorder to transact on the permissioned blockchain 304. Meanwhile, a userattempting to utilize chaincode may be required to verify theircredentials on the traditional data source 312. To confirm the user'sauthorization, chaincode can use an out-of-band connection to this datathrough a traditional processing platform 318.

FIG. 3B illustrates another example of a permissioned blockchain network320, which features a distributed, decentralized peer-to-peerarchitecture. In this example, a blockchain user 322 may submit atransaction to the permissioned blockchain 324. In this example, thetransaction can be a deploy, invoke, or query, and may be issued througha client-side application leveraging an SDK, directly through an API,etc. Networks may provide access to a regulator 326, such as an auditor.A blockchain network operator 328 manages member permissions, such asenrolling the regulator 326 as an “auditor” and the blockchain user 322as a “client”. An auditor could be restricted only to querying theledger whereas a client could be authorized to deploy, invoke, and querycertain types of chaincode.

A blockchain developer 330 writes chaincode and client-sideapplications. The blockchain developer 330 can deploy chaincode directlyto the network through an interface. To include credentials from atraditional data source 332 in chaincode, the developer 330 could use anout-of-band connection to access the data. In this example, theblockchain user 322 connects to the network through a peer node 334.Before proceeding with any transactions, the peer node 334 retrieves theuser's enrollment and transaction certificates from the certificateauthority 336. In some cases, blockchain users must possess thesedigital certificates in order to transact on the permissioned blockchain324. Meanwhile, a user attempting to utilize chaincode may be requiredto verify their credentials on the traditional data source 332. Toconfirm the user's authorization, chaincode can use an out-of-bandconnection to this data through a traditional processing platform 338.

In some embodiments, the blockchain herein may be a permissionlessblockchain. In contrast with permissioned blockchains which requirepermission to join, anyone can join a permissionless blockchain. Forexample, to join a permissionless blockchain a user may create apersonal address and begin interacting with the network, by submittingtransactions, and hence adding entries to the ledger. Additionally, allparties have the choice of running a node on the system and employingthe mining protocols to help verify transactions.

FIG. 3C illustrates a process 350 of a transaction being processed by apermissionless blockchain 352 including a plurality of nodes 354. Asender 356 desires to send payment or some other form of value (e.g., adeed, medical records, a contract, a good, a service, or any other assetthat can be encapsulated in a digital record) to a recipient 358 via thepermissionless blockchain 352. In one embodiment, each of the senderdevice 356 and the recipient device 358 may have digital wallets(associated with the blockchain 352) that provide user interfacecontrols and a display of transaction parameters. In response, thetransaction is broadcast throughout the blockchain 352 to the nodes 354.Depending on the blockchain's 352 network parameters the nodes verify360 the transaction based on rules (which may be pre-defined ordynamically allocated) established by the permissionless blockchain 352creators. For example, this may include verifying identities of theparties involved, etc. The transaction may be verified immediately or itmay be placed in a queue with other transactions and the nodes 354determine if the transactions are valid based on a set of network rules.

In structure 362, valid transactions are formed into a block and sealedwith a lock (hash). This process may be performed by mining nodes amongthe nodes 354. Mining nodes may utilize additional software specificallyfor mining and creating blocks for the permissionless blockchain 352.Each block may be identified by a hash (e.g., 256 bit number, etc.)created using an algorithm agreed upon by the network. Each block mayinclude a header, a pointer or reference to a hash of a previous block'sheader in the chain, and a group of valid transactions. The reference tothe previous block's hash is associated with the creation of the secureindependent chain of blocks.

Before blocks can be added to the blockchain, the blocks must bevalidated. Validation for the permissionless blockchain 352 may includea proof-of-work (PoW) which is a solution to a puzzle derived from theblock's header. Although not shown in the example of FIG. 3C, anotherprocess for validating a block is proof-of-stake. Unlike theproof-of-work, where the algorithm rewards miners who solve mathematicalproblems, with the proof of stake, a creator of a new block is chosen ina deterministic way, depending on its wealth, also defined as “stake.”Then, a similar proof is performed by the selected/chosen node.

With mining 364, nodes try to solve the block by making incrementalchanges to one variable until the solution satisfies a network-widetarget. This creates the PoW thereby ensuring correct answers. In otherwords, a potential solution must prove that computing resources weredrained in solving the problem. In some types of permissionlessblockchains, miners may be rewarded with value (e.g., coins, etc.) forcorrectly mining a block.

Here, the PoW process, alongside the chaining of blocks, makesmodifications of the blockchain extremely difficult, as an attacker mustmodify all subsequent blocks in order for the modifications of one blockto be accepted. Furthermore, as new blocks are mined, the difficulty ofmodifying a block increases, and the number of subsequent blocksincreases. With distribution 366, the successfully validated block isdistributed through the permissionless blockchain 352 and all nodes 354add the block to a majority chain which is the permissionlessblockchain's 352 auditable ledger. Furthermore, the value in thetransaction submitted by the sender 356 is deposited or otherwisetransferred to the digital wallet of the recipient device 358.

FIG. 4 illustrates a system messaging diagram 400 for performing blockintegrity checking, according to example embodiments. Referring to FIG.4, the system diagram 400 includes an orderer peer 410, a peripheralpeer 420 and other peripheral peers 430.

The orderer peer 410 creates a new block 415, and distributes the newblock 416 to the peripheral peer 420 and other peripheral peers 430. Theperipheral peer 420 calculates a hash of the new block 425A in parallelwith the other peripheral peers 430 calculating a hash of the new block425N. The peripheral peer 420 transfers a request 426 to the otherperipheral peers 430 to provide hashes of the new block 416. Asdescribed with respect to FIG. 1A, the other peripheral peers 430conduct the same processes in parallel. Thus, the same processesperformed by the other peripheral peers 430 are represented by an “N”suffix, while those processes performed by the peripheral peer 420 arerepresented by an “A” suffix. The request hashes 426 and requestedhashes 427 are both represented with bidirectional arrows toadditionally represent this parallelism. However, only the blocksexecuted by the peripheral peer 420 are specifically discussed herein.The other peripheral peers 430 constitute a majority of the peripheralpeers in the network.

In response to receiving the request 426, each of the other peripheralpeers 430 provides the requested hashes 427 to the peripheral peer 420.The peripheral peer 420 compares the calculated hash to the requestedhashes 435A, and determines if all of the requested hashes are identicalto the calculated hash 440A. If all of the requested hashes areidentical to the calculated hash 440A, the peripheral peer 420 commitsthe new block to the blockchain network 445A. Next, the peripheral peer420 determines that all of the requested hashes are not identical to thecalculated hash 440A (i.e. a miscompared has occurred) 450A. In thiscase, the peripheral peer 420 ceases committing new blocks to theblockchain network 455A.

FIG. 5A illustrates a flow diagram 500 of an example method of verifyinga new block in a blockchain, according to example embodiments. Referringto FIG. 5A, the method 500 may include one or more of the followingsteps.

At block 504, an orderer peer creates a new block, and distributes thenew block to peers of the blockchain network.

At block 508, peripheral peers of the blockchain network calculate ahash of the new block.

At block 512, each of the peripheral peers obtain new block hashes froma majority of peripheral peers of the same blockchain network.

At block 516, each peripheral peer compares the calculated new blockhash with the obtained hashes from the majority of peripheral peers.

At block 520, if any of the hashes miscompared, each of the peripheralpeers that observed a miscompare obtains blocks corresponding to themiscompared hashes from those peripheral peers that supplied themiscompared hashes.

At block 524, the peripheral peer ceases committing blocks if any of theobtained blocks miscompared to the new block. This signifies that amalicious orderer peer created a bad block.

FIG. 5B illustrates a flow diagram 530 of an example method of verifyinga sequence of blocks in a blockchain, according to example embodiments.Referring to FIG. 5B, the method 530 may include one or more of thefollowing steps.

At block 534, an orderer peer creates a sequence of blocks, anddistributes the new sequence of blocks to peers of the blockchainnetwork.

At block 538, peripheral peers of the blockchain network calculatehashes of the new sequence of blocks.

At block 542, each of the peripheral peers adds the calculated hashes toits own merkle tree, where each leaf node of the merkle tree stores ahash of a different block.

At block 546, each peripheral peer requests merkle tree root node hashesfrom a majority of other peripheral peers of the blockchain network.Each peripheral peer compares its own merkle tree root node hash tomerkle tree root node hashes it receives from the other peripheral peersit sent the request to.

At block 550, if any of the root node hashes miscompared, each of theperipheral peers that observed a miscompare obtains sequences of blockscorresponding to the miscompared root node hashes from those peripheralpeers that supplied the miscompared root node hashes.

At block 554, the peripheral peer ceases committing blocks if any of theobtained sequence of blocks miscompared to the new sequence of blocks.This signifies that a malicious orderer peer created a bad sequence ofblocks.

FIG. 5C illustrates a flow diagram 560 of an example method ofpreventing vulnerabilities in a blockchain, according to exampleembodiments. Referring to FIG. 5C, the method 560 may include one ormore of the following steps.

At block 564, crosslink transactions are submitted. A first crosslinktransaction is submitted for addition to a first blockchain and a secondcorresponding crosslink transaction is submitted for addition to asecond blockchain, e.g., by a computing device associated with a partyor user of the first and second blockchains. For example, the firstcrosslink transaction may be submitted to nodes associated withblockchain A for addition to blockchain A and the second crosslinktransaction may be submitted to nodes associated with blockchain B foraddition to blockchain B. In some aspects, for example, the user maysubmit the corresponding crosslink transactions when the useranticipates that one of blockchains A and B may become quiescent in thefuture. In some aspects, for example, the corresponding crosslinktransactions may be submitted at the same time. In some aspects, forexample, the first and second crosslink transactions may be submitted tothe first and second blockchains at about the same time, e.g., within afew seconds, minutes, or hours of each other. In some aspects, one ofthe crosslink transactions may first be submitted to the blockchain thathas a higher rate of block additions followed by the submission of theother crosslink transaction to the blockchain that has a lower rate ofblock additions. For example, the busiest blockchain may receive thesubmission of the crosslink transaction first followed by the less busyblockchain. In some aspects, for example, once the crosslink transactionhas been confirmed as present in a new block on the busiest blockchain,the corresponding crosslink transaction may be submitted to the lessbusy blockchain. In some aspects, for example, this may be reversedwhere the crosslink transaction may be submitted to the less busyblockchain first followed by the busiest blockchain second.

At block 568, 1^(st) and 2^(nd) blockchains are queried. A computingdevice of a user, e.g., the same user or another user of one or both ofblockchains A and B, may query the first blockchain, e.g., blockchain Afor the first crosslink transaction. This user may query blockchain A,for example, in response to blockchain B entering a period ofquiescence. For example, the user may initially determine thatblockchain B has entered a period of quiescence and may know or identifythat blockchains A and B have been crosslinked through crosslinktransactions. For example, the user may determine that blockchains A andB have been crosslinked by querying blockchain B to see if there wereany past crosslink transactions and identifying blockchain A as ablockchain having had a corresponding crosslink transaction to one foundin blockchain B. The computing device of the user may identify thesecond blockchain, e.g., blockchain B, based on the queried firstcrosslink transaction, for example, by viewing the ID to blockchain B(FIG. 4). The computing device of the user may query the secondblockchain for the corresponding second crosslink transaction based onthe identification of the second blockchain based on the first crosslinktransaction.

At block 572, the crosslink transactions are compared. If the secondcrosslink transaction is present in the second blockchain, the secondcrosslink transaction may be compared to the first crosslink transactionto determine whether the second crosslink transaction corresponds to thefirst crosslink transaction. For example, transaction digests may beaccessed or decoded using a public key of the user that submitted thecrosslink transactions. If the transaction digests are decoded using thesame public key, the crosslink transactions may be validated since ithas been confirmed that the same user submitted both crosslinktransactions.

At block 576, a check is made to determine if the 2^(nd) blockchainshould be invalidated. The computing device of the user may determinebased on a result of the query whether the corresponding secondcrosslink transaction is or is not present. If the second crosslinktransaction is not present in the second blockchain, at least a portionof the second blockchain may be invalidated. For example, the lack ofthe second crosslink transaction may be an indication that at least partof the second blockchain has been modified or tampered with. In someaspects, the user may utilize prior corresponding crosslink transactionsof the first and second blockchains to validate at least a portion ofthe blockchain. For example, if a crosslink transaction is missing forblockchain B, the user may instead try to validate at least the portionof blockchain B ending at the corresponding crosslink transaction.

At block 580, the 2^(nd) blockchain is validated. If the secondcrosslink transaction is determined to correspond to the first crosslinktransaction based on the comparison, the second blockchain may bevalidated. Alternatively, if the second crosslink transaction isdetermined to not correspond to the first crosslink transaction, thesecond blockchain may be invalidated. For example, if the public keydoes not decode one or both of the transaction digests, the user willknow that at least one of the crosslink transactions was not submittedby the same user and therefore that the second crosslink transaction isinvalid as evidence of security and integrity on the second blockchainand therefore at least a portion of the second blockchain isinvalidated.

FIG. 6A illustrates an example system 600 that includes a physicalinfrastructure 610 configured to perform various operations according toexample embodiments. Referring to FIG. 6A, the physical infrastructure610 includes a module 612 and a module 614. The module 614 includes ablockchain 620 and a smart contract 630 (which may reside on theblockchain 620), that may execute any of the operational steps 608 (inmodule 612) included in any of the example embodiments. Thesteps/operations 608 may include one or more of the embodimentsdescribed or depicted and may represent output or written informationthat is written or read from one or more smart contracts 630 and/orblockchains 620. The physical infrastructure 610, the module 612, andthe module 614 may include one or more computers, servers, processors,memories, and/or wireless communication devices. Further, the module 612and the module 614 may be a same module.

FIG. 6B illustrates another example system 640 configured to performvarious operations according to example embodiments. Referring to FIG.6B, the system 640 includes a module 612 and a module 614. The module614 includes a blockchain 620 and a smart contract 630 (which may resideon the blockchain 620), that may execute any of the operational steps608 (in module 612) included in any of the example embodiments. Thesteps/operations 608 may include one or more of the embodimentsdescribed or depicted and may represent output or written informationthat is written or read from one or more smart contracts 630 and/orblockchains 620. The physical infrastructure 610, the module 612, andthe module 614 may include one or more computers, servers, processors,memories, and/or wireless communication devices. Further, the module 612and the module 614 may be a same module.

FIG. 6C illustrates an example system configured to utilize a smartcontract configuration among contracting parties and a mediating serverconfigured to enforce the smart contract terms on the blockchainaccording to example embodiments. Referring to FIG. 6C, theconfiguration 650 may represent a communication session, an assettransfer session or a process or procedure that is driven by a smartcontract 630 which explicitly identifies one or more user devices 652and/or 656. The execution, operations and results of the smart contractexecution may be managed by a server 654. Content of the smart contract630 may require digital signatures by one or more of the entities 652and 656 which are parties to the smart contract transaction. The resultsof the smart contract execution may be written to a blockchain 620 as ablockchain transaction. The smart contract 630 resides on the blockchain620 which may reside on one or more computers, servers, processors,memories, and/or wireless communication devices.

FIG. 6D illustrates a system 660 including a blockchain, according toexample embodiments. Referring to the example of FIG. 6D, an applicationprogramming interface (API) gateway 662 provides a common interface foraccessing blockchain logic (e.g., smart contract 630 or other chaincode)and data (e.g., distributed ledger, etc.). In this example, the APIgateway 662 is a common interface for performing transactions (invoke,queries, etc.) on the blockchain by connecting one or more entities 652and 656 to a blockchain peer (i.e., server 654). Here, the server 654 isa blockchain network peer component that holds a copy of the world stateand a distributed ledger allowing clients 652 and 656 to query data onthe world state as well as submit transactions into the blockchainnetwork where, depending on the smart contract 630 and endorsementpolicy, endorsing peers will run the smart contracts 630.

The above embodiments may be implemented in hardware, in a computerprogram executed by a processor, in firmware, or in a combination of theabove. A computer program may be embodied on a computer readable medium,such as a storage medium. For example, a computer program may reside inrandom access memory (“RAM”), flash memory, read-only memory (“ROM”),erasable programmable read-only memory (“EPROM”), electrically erasableprogrammable read-only memory (“EEPROM”), registers, hard disk, aremovable disk, a compact disk read-only memory (“CD-ROM”), or any otherform of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such thatthe processor may read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anapplication specific integrated circuit (“ASIC”). In the alternative,the processor and the storage medium may reside as discrete components.

FIG. 7A illustrates a process 700 of a new block being added to adistributed ledger 720, according to example embodiments, and FIG. 7Billustrates contents of a new data block structure 730 for blockchain,according to example embodiments. Referring to FIG. 7A, clients (notshown) may submit transactions to blockchain nodes 711, 712, and/or 713.Clients may be instructions received from any source to enact activityon the blockchain 720. As an example, clients may be applications thatact on behalf of a requester, such as a device, person or entity topropose transactions for the blockchain. The plurality of blockchainpeers (e.g., blockchain nodes 711, 712, and 713) may maintain a state ofthe blockchain network and a copy of the distributed ledger 720.Different types of blockchain nodes/peers may be present in theblockchain network including endorsing peers which simulate and endorsetransactions proposed by clients and committing peers which verifyendorsements, validate transactions, and commit transactions to thedistributed ledger 720. In this example, the blockchain nodes 711, 712,and 713 may perform the role of endorser node, committer node, or both.

The distributed ledger 720 includes a blockchain which stores immutable,sequenced records in blocks, and a state database 724 (current worldstate) maintaining a current state of the blockchain 722. Onedistributed ledger 720 may exist per channel and each peer maintains itsown copy of the distributed ledger 720 for each channel of which theyare a member. The blockchain 722 is a transaction log, structured ashash-linked blocks where each block contains a sequence of Ntransactions. Blocks may include various components such as shown inFIG. 7B. The linking of the blocks (shown by arrows in FIG. 7A) may begenerated by adding a hash of a prior block's header within a blockheader of a current block. In this way, all transactions on theblockchain 722 are sequenced and cryptographically linked togetherpreventing tampering with blockchain data without breaking the hashlinks. Furthermore, because of the links, the latest block in theblockchain 722 represents every transaction that has come before it. Theblockchain 722 may be stored on a peer file system (local or attachedstorage), which supports an append-only blockchain workload.

The current state of the blockchain 722 and the distributed ledger 722may be stored in the state database 724. Here, the current state datarepresents the latest values for all keys ever included in the chaintransaction log of the blockchain 722. Chaincode invocations executetransactions against the current state in the state database 724. Tomake these chaincode interactions extremely efficient, the latest valuesof all keys are stored in the state database 724. The state database 724may include an indexed view into the transaction log of the blockchain722, it can therefore be regenerated from the chain at any time. Thestate database 724 may automatically get recovered (or generated ifneeded) upon peer startup, before transactions are accepted.

Endorsing nodes receive transactions from clients and endorse thetransaction based on simulated results. Endorsing nodes hold smartcontracts which simulate the transaction proposals. When an endorsingnode endorses a transaction, the endorsing nodes creates a transactionendorsement which is a signed response from the endorsing node to theclient application indicating the endorsement of the simulatedtransaction. The method of endorsing a transaction depends on anendorsement policy which may be specified within chaincode. An exampleof an endorsement policy is “the majority of endorsing peers mustendorse the transaction”. Different channels may have differentendorsement policies. Endorsed transactions are forward by the clientapplication to ordering service 710.

The ordering service 710 accepts endorsed transactions, orders them intoa block, and delivers the blocks to the committing peers. For example,the ordering service 710 may initiate a new block when a threshold oftransactions has been reached, a timer times out, or another condition.In the example of FIG. 7A, blockchain node 712 is a committing peer thathas received a new data new data block 730 for storage on blockchain720. The first block in the blockchain may be referred to as a genesisblock which includes information about the blockchain, its members, thedata stored therein, etc.

The ordering service 710 may be made up of a cluster of orderers. Theordering service 710 does not process transactions, smart contracts, ormaintain the shared ledger. Rather, the ordering service 710 may acceptthe endorsed transactions and specifies the order in which thosetransactions are committed to the distributed ledger 720. Thearchitecture of the blockchain network may be designed such that thespecific implementation of ‘ordering’ (e.g., Solo, Kafka, BFT, etc.)becomes a pluggable component.

Transactions are written to the distributed ledger 720 in a consistentorder. The order of transactions is established to ensure that theupdates to the state database 724 are valid when they are committed tothe network. Unlike a cryptocurrency blockchain system (e.g., Bitcoin,etc.) where ordering occurs through the solving of a cryptographicpuzzle, or mining, in this example the parties of the distributed ledger720 may choose the ordering mechanism that best suits that network.

When the ordering service 710 initializes a new data block 730, the newdata block 730 may be broadcast to committing peers (e.g., blockchainnodes 711, 712, and 713). In response, each committing peer validatesthe transaction within the new data block 730 by checking to make surethat the read set and the write set still match the current world statein the state database 724. Specifically, the committing peer candetermine whether the read data that existed when the endorserssimulated the transaction is identical to the current world state in thestate database 724. When the committing peer validates the transaction,the transaction is written to the blockchain 722 on the distributedledger 720, and the state database 724 is updated with the write datafrom the read-write set. If a transaction fails, that is, if thecommitting peer finds that the read-write set does not match the currentworld state in the state database 724, the transaction ordered into ablock will still be included in that block, but it will be marked asinvalid, and the state database 724 will not be updated.

Referring to FIG. 7B, a new data block 730 (also referred to as a datablock) that is stored on the blockchain 722 of the distributed ledger720 may include multiple data segments such as a block header 740, blockdata 750, and block metadata 760. It should be appreciated that thevarious depicted blocks and their contents, such as new data block 730and its contents. shown in FIG. 7B are merely examples and are not meantto limit the scope of the example embodiments. The new data block 730may store transactional information of N transaction(s) (e.g., 1, 10,100, 500, 1000, 2000, 3000, etc.) within the block data 750. The newdata block 730 may also include a link to a previous block (e.g., on theblockchain 722 in FIG. 7A) within the block header 740. In particular,the block header 740 may include a hash of a previous block's header.The block header 740 may also include a unique block number, a hash ofthe block data 750 of the new data block 730, and the like. The blocknumber of the new data block 730 may be unique and assigned in variousorders, such as an incremental/sequential order starting from zero.

The block data 750 may store transactional information of eachtransaction that is recorded within the new data block 730. For example,the transaction data may include one or more of a type of thetransaction, a version, a timestamp, a channel ID of the distributedledger 720, a transaction ID, an epoch, a payload visibility, achaincode path (deploy tx), a chaincode name, a chaincode version, input(chaincode and functions), a client (creator) identify such as a publickey and certificate, a signature of the client, identities of endorsers,endorser signatures, a proposal hash, chaincode events, response status,namespace, a read set (list of key and version read by the transaction,etc.), a write set (list of key and value, etc.), a start key, an endkey, a list of keys, a Merkel tree query summary, and the like. Thetransaction data may be stored for each of the N transactions.

In some embodiments, the block data 750 may also store new data 762which adds additional information to the hash-linked chain of blocks inthe blockchain 722. The additional information includes one or more ofthe steps, features, processes and/or actions described or depictedherein. Accordingly, the new data 762 can be stored in an immutable logof blocks on the distributed ledger 720. Some of the benefits of storingsuch new data 762 are reflected in the various embodiments disclosed anddepicted herein. Although in FIG. 7B the new data 762 is depicted in theblock data 750 but could also be located in the block header 740 or theblock metadata 760.

The block metadata 760 may store multiple fields of metadata (e.g., as abyte array, etc.). Metadata fields may include signature on blockcreation, a reference to a last configuration block, a transactionfilter identifying valid and invalid transactions within the block, lastoffset persisted of an ordering service that ordered the block, and thelike. The signature, the last configuration block, and the orderermetadata may be added by the ordering service 710. Meanwhile, acommitter of the block (such as blockchain node 712) may addvalidity/invalidity information based on an endorsement policy,verification of read/write sets, and the like. The transaction filtermay include a byte array of a size equal to the number of transactionsin the block data 750 and a validation code identifying whether atransaction was valid/invalid.

FIG. 7C illustrates an embodiment of a blockchain 770 for digitalcontent in accordance with the embodiments described herein. The digitalcontent may include one or more files and associated information. Thefiles may include media, images, video, audio, text, links, graphics,animations, web pages, documents, or other forms of digital content. Theimmutable, append-only aspects of the blockchain serve as a safeguard toprotect the integrity, validity, and authenticity of the digitalcontent, making it suitable use in legal proceedings where admissibilityrules apply or other settings where evidence is taken in toconsideration or where the presentation and use of digital informationis otherwise of interest. In this case, the digital content may bereferred to as digital evidence.

The blockchain may be formed in various ways. In one embodiment, thedigital content may be included in and accessed from the blockchainitself. For example, each block of the blockchain may store a hash valueof reference information (e.g., header, value, etc.) along theassociated digital content. The hash value and associated digitalcontent may then be encrypted together. Thus, the digital content ofeach block may be accessed by decrypting each block in the blockchain,and the hash value of each block may be used as a basis to reference aprevious block. This may be illustrated as follows:

Block 1 Block 2 . . . Block N Hash Value 1 Hash Value 2 Hash Value NDigital Content 1 Digital Content 2 Digital Content N

In one embodiment, the digital content may be not included in theblockchain. For example, the blockchain may store the encrypted hashesof the content of each block without any of the digital content. Thedigital content may be stored in another storage area or memory addressin association with the hash value of the original file. The otherstorage area may be the same storage device used to store the blockchainor may be a different storage area or even a separate relationaldatabase. The digital content of each block may be referenced oraccessed by obtaining or querying the hash value of a block of interestand then looking up that has value in the storage area, which is storedin correspondence with the actual digital content. This operation may beperformed, for example, a database gatekeeper. This may be illustratedas follows:

Blockchain Storage Area Block 1 Hash Value Block 1 Hash Value . . .Content . . . . . . Block N Hash Value Block N Hash Value . . . Content

In the example embodiment of FIG. 7C, the blockchain 770 includes anumber of blocks 778 ₁, 778 ₂, . . . 778 _(N) cryptographically linkedin an ordered sequence, where N≥1. The encryption used to link theblocks 778 ₁, 778 ₂, . . . 778 _(N) may be any of a number of keyed orun-keyed Hash functions. In one embodiment, the blocks 778 ₁, 778 ₂, . .. 778 _(N) are subject to a hash function which produces n-bitalphanumeric outputs (where n is 256 or another number) from inputs thatare based on information in the blocks. Examples of such a hash functioninclude, but are not limited to, a SHA-type (SHA stands for Secured HashAlgorithm) algorithm, Merkle-Damgard algorithm, HAIFA algorithm,Merkle-tree algorithm, nonce-based algorithm, and anon-collision-resistant PRF algorithm. In another embodiment, the blocks778 ₁, 778 ₂, . . . , 778 _(N) may be cryptographically linked by afunction that is different from a hash function. For purposes ofillustration, the following description is made with reference to a hashfunction, e.g., SHA-2.

Each of the blocks 778 ₁, 778 ₂, . . . , 778 _(N) in the blockchainincludes a header, a version of the file, and a value. The header andthe value are different for each block as a result of hashing in theblockchain. In one embodiment, the value may be included in the header.As described in greater detail below, the version of the file may be theoriginal file or a different version of the original file.

The first block 778 ₁ in the blockchain is referred to as the genesisblock and includes the header 772 ₁, original file 774 ₁, and an initialvalue 776 ₁. The hashing scheme used for the genesis block, and indeedin all subsequent blocks, may vary. For example, all the information inthe first block 778 ₁ may be hashed together and at one time, or each ora portion of the information in the first block 778 ₁ may be separatelyhashed and then a hash of the separately hashed portions may beperformed.

The header 772 ₁ may include one or more initial parameters, which, forexample, may include a version number, timestamp, nonce, rootinformation, difficulty level, consensus protocol, duration, mediaformat, source, descriptive keywords, and/or other informationassociated with original file 774 ₁ and/or the blockchain. The header772 ₁ may be generated automatically (e.g., by blockchain networkmanaging software) or manually by a blockchain participant. Unlike theheader in other blocks 778 ₂ to 778 _(N) in the blockchain, the header772 ₁ in the genesis block does not reference a previous block, simplybecause there is no previous block.

The original file 774 ₁ in the genesis block may be, for example, dataas captured by a device with or without processing prior to itsinclusion in the blockchain. The original file 774 ₁ is received throughthe interface of the system from the device, media source, or node. Theoriginal file 774 ₁ is associated with metadata, which, for example, maybe generated by a user, the device, and/or the system processor, eithermanually or automatically. The metadata may be included in the firstblock 778 ₁ in association with the original file 774 ₁.

The value 776 ₁ in the genesis block is an initial value generated basedon one or more unique attributes of the original file 774 ₁. In oneembodiment, the one or more unique attributes may include the hash valuefor the original file 774 ₁, metadata for the original file 774 ₁, andother information associated with the file. In one implementation, theinitial value 776 ₁ may be based on the following unique attributes:

-   -   1) SHA-2 computed hash value for the original file    -   2) originating device ID    -   3) starting timestamp for the original file    -   4) initial storage location of the original file    -   5) blockchain network member ID for software to currently        control the original file and associated metadata

The other blocks 778 ₂ to 778 _(N) in the blockchain also have headers,files, and values. However, unlike the first block 772 ₁, each of theheaders 772 ₂ to 772 _(N) in the other blocks includes the hash value ofan immediately preceding block. The hash value of the immediatelypreceding block may be just the hash of the header of the previous blockor may be the hash value of the entire previous block. By including thehash value of a preceding block in each of the remaining blocks, a tracecan be performed from the Nth block back to the genesis block (and theassociated original file) on a block-by-block basis, as indicated byarrows 780, to establish an auditable and immutable chain-of-custody.

Each of the header 772 ₂ to 772 _(N) in the other blocks may alsoinclude other information, e.g., version number, timestamp, nonce, rootinformation, difficulty level, consensus protocol, and/or otherparameters or information associated with the corresponding files and/orthe blockchain in general.

The files 774 ₂ to 774 _(N) in the other blocks may be equal to theoriginal file or may be a modified version of the original file in thegenesis block depending, for example, on the type of processingperformed. The type of processing performed may vary from block toblock. The processing may involve, for example, any modification of afile in a preceding block, such as redacting information or otherwisechanging the content of, taking information away from, or adding orappending information to the files.

Additionally, or alternatively, the processing may involve merelycopying the file from a preceding block, changing a storage location ofthe file, analyzing the file from one or more preceding blocks, movingthe file from one storage or memory location to another, or performingaction relative to the file of the blockchain and/or its associatedmetadata. Processing which involves analyzing a file may include, forexample, appending, including, or otherwise associating variousanalytics, statistics, or other information associated with the file.

The values in each of the other blocks 776 ₂ to 776 _(N) in the otherblocks are unique values and are all different as a result of theprocessing performed. For example, the value in any one blockcorresponds to an updated version of the value in the previous block.The update is reflected in the hash of the block to which the value isassigned. The values of the blocks therefore provide an indication ofwhat processing was performed in the blocks and also permit a tracingthrough the blockchain back to the original file. This tracking confirmsthe chain-of-custody of the file throughout the entire blockchain.

For example, consider the case where portions of the file in a previousblock are redacted, blocked out, or pixelated in order to protect theidentity of a person shown in the file. In this case, the blockincluding the redacted file will include metadata associated with theredacted file, e.g., how the redaction was performed, who performed theredaction, timestamps where the redaction(s) occurred, etc. The metadatamay be hashed to form the value. Because the metadata for the block isdifferent from the information that was hashed to form the value in theprevious block, the values are different from one another and may berecovered when decrypted.

In one embodiment, the value of a previous block may be updated (e.g., anew hash value computed) to form the value of a current block when anyone or more of the following occurs. The new hash value may be computedby hashing all or a portion of the information noted below, in thisexample embodiment.

-   -   a) new SHA-2 computed hash value if the file has been processed        in any way (e.g., if the file was redacted, copied, altered,        accessed, or some other action was taken)    -   b) new storage location for the file    -   c) new metadata identified associated with the file    -   d) transfer of access or control of the file from one blockchain        participant to another blockchain participant

FIG. 7D illustrates an embodiment of a block which may represent thestructure of the blocks in the blockchain 790 in accordance with oneembodiment. The block, Block_(i), includes a header 772 ₁, a file 774_(i), and a value 776 ₁.

The header 772 ₁ includes a hash value of a previous block Block_(i−1)and additional reference information, which, for example, may be any ofthe types of information (e.g., header information including references,characteristics, parameters, etc.) discussed herein. All blocksreference the hash of a previous block except, of course, the genesisblock. The hash value of the previous block may be just a hash of theheader in the previous block or a hash of all or a portion of theinformation in the previous block, including the file and metadata.

The file 774 _(i) includes a plurality of data, such as Data 1, Data 2,. . . , Data N in sequence. The data are tagged with metadata Metadata1, Metadata 2, . . . , Metadata N which describe the content and/orcharacteristics associated with the data. For example, the metadata foreach data may include information to indicate a timestamp for the data,process the data, keywords indicating the persons or other contentdepicted in the data, and/or other features that may be helpful toestablish the validity and content of the file as a whole, andparticularly its use a digital evidence, for example, as described inconnection with an embodiment discussed below. In addition to themetadata, each data may be tagged with reference REF₁, REF₂, . . . ,REF_(N) to a previous data to prevent tampering, gaps in the file, andsequential reference through the file.

Once the metadata is assigned to the data (e.g., through a smartcontract), the metadata cannot be altered without the hash changing,which can easily be identified for invalidation. The metadata, thus,creates a data log of information that may be accessed for use byparticipants in the blockchain.

The value 776 _(i) is a hash value or other value computed based on anyof the types of information previously discussed. For example, for anygiven block Block_(i), the value for that block may be updated toreflect the processing that was performed for that block, e.g., new hashvalue, new storage location, new metadata for the associated file,transfer of control or access, identifier, or other action orinformation to be added. Although the value in each block is shown to beseparate from the metadata for the data of the file and header, thevalue may be based, in part or whole, on this metadata in anotherembodiment.

Once the blockchain 770 is formed, at any point in time, the immutablechain-of-custody for the file may be obtained by querying the blockchainfor the transaction history of the values across the blocks. This query,or tracking procedure, may begin with decrypting the value of the blockthat is most currently included (e.g., the last (N^(th)) block), andthen continuing to decrypt the value of the other blocks until thegenesis block is reached and the original file is recovered. Thedecryption may involve decrypting the headers and files and associatedmetadata at each block, as well.

Decryption is performed based on the type of encryption that took placein each block. This may involve the use of private keys, public keys, ora public key-private key pair. For example, when asymmetric encryptionis used, blockchain participants or a processor in the network maygenerate a public key and private key pair using a predeterminedalgorithm. The public key and private key are associated with each otherthrough some mathematical relationship. The public key may bedistributed publicly to serve as an address to receive messages fromother users, e.g., an IP address or home address. The private key iskept secret and used to digitally sign messages sent to other blockchainparticipants. The signature is included in the message so that therecipient can verify using the public key of the sender. This way, therecipient can be sure that only the sender could have sent this message.

Generating a key pair may be analogous to creating an account on theblockchain, but without having to actually register anywhere. Also,every transaction that is executed on the blockchain is digitally signedby the sender using their private key. This signature ensures that onlythe owner of the account can track and process (if within the scope ofpermission determined by a smart contract) the file of the blockchain.

FIGS. 8A and 8B illustrate additional examples of use cases forblockchain which may be incorporated and used herein. In particular,FIG. 8A illustrates an example 800 of a blockchain 810 which storesmachine learning (artificial intelligence) data. Machine learning relieson vast quantities of historical data (or training data) to buildpredictive models for accurate prediction on new data. Machine learningsoftware (e.g., neural networks, etc.) can often sift through millionsof records to unearth non-intuitive patterns.

In the example of FIG. 8A, a host platform 820 builds and deploys amachine learning model for predictive monitoring of assets 830. Here,the host platform 820 may be a cloud platform, an industrial server, aweb server, a personal computer, a user device, and the like. Assets 830can be any type of asset (e.g., machine or equipment, etc.) such as anaircraft, locomotive, turbine, medical machinery and equipment, oil andgas equipment, boats, ships, vehicles, and the like. As another example,assets 830 may be non-tangible assets such as stocks, currency, digitalcoins, insurance, or the like.

The blockchain 810 can be used to significantly improve both a trainingprocess 802 of the machine learning model and a predictive process 804based on a trained machine learning model. For example, in 802, ratherthan requiring a data scientist/engineer or other user to collect thedata, historical data may be stored by the assets 830 themselves (orthrough an intermediary, not shown) on the blockchain 810. This cansignificantly reduce the collection time needed by the host platform 820when performing predictive model training. For example, using smartcontracts, data can be directly and reliably transferred straight fromits place of origin to the blockchain 810. By using the blockchain 810to ensure the security and ownership of the collected data, smartcontracts may directly send the data from the assets to the individualsthat use the data for building a machine learning model. This allows forsharing of data among the assets 830.

The collected data may be stored in the blockchain 810 based on aconsensus mechanism. The consensus mechanism pulls in (permissionednodes) to ensure that the data being recorded is verified and accurate.The data recorded is time-stamped, cryptographically signed, andimmutable. It is therefore auditable, transparent, and secure. AddingIoT devices which write directly to the blockchain can, in certain cases(i.e. supply chain, healthcare, logistics, etc.), increase both thefrequency and accuracy of the data being recorded.

Furthermore, training of the machine learning model on the collecteddata may take rounds of refinement and testing by the host platform 820.Each round may be based on additional data or data that was notpreviously considered to help expand the knowledge of the machinelearning model. In 802, the different training and testing steps (andthe data associated therewith) may be stored on the blockchain 810 bythe host platform 820. Each refinement of the machine learning model(e.g., changes in variables, weights, etc.) may be stored on theblockchain 810. This provides verifiable proof of how the model wastrained and what data was used to train the model. Furthermore, when thehost platform 820 has achieved a finally trained model, the resultingmodel may be stored on the blockchain 810.

After the model has been trained, it may be deployed to a liveenvironment where it can make predictions/decisions based on theexecution of the final trained machine learning model. For example, in804, the machine learning model may be used for condition-basedmaintenance (CBM) for an asset such as an aircraft, a wind turbine, ahealthcare machine, and the like. In this example, data fed back fromthe asset 830 may be input the machine learning model and used to makeevent predictions such as failure events, error codes, and the like.Determinations made by the execution of the machine learning model atthe host platform 820 may be stored on the blockchain 810 to provideauditable/verifiable proof. As one non-limiting example, the machinelearning model may predict a future breakdown/failure to a part of theasset 830 and create alert or a notification to replace the part. Thedata behind this decision may be stored by the host platform 820 on theblockchain 810. In one embodiment the features and/or the actionsdescribed and/or depicted herein can occur on or with respect to theblockchain 810.

New transactions for a blockchain can be gathered together into a newblock and added to an existing hash value. This is then encrypted tocreate a new hash for the new block. This is added to the next list oftransactions when they are encrypted, and so on. The result is a chainof blocks that each contain the hash values of all preceding blocks.Computers that store these blocks regularly compare their hash values toensure that they are all in agreement. Any computer that does not agree,discards the records that are causing the problem. This approach is goodfor ensuring tamper-resistance of the blockchain, but it is not perfect.

One way to game this system is for a dishonest user to change the listof transactions in their favor, but in a way that leaves the hashunchanged. This can be done by brute force, in other words by changing arecord, encrypting the result, and seeing whether the hash value is thesame. And if not, trying again and again and again until it finds a hashthat matches. The security of blockchains is based on the belief thatordinary computers can only perform this kind of brute force attack overtime scales that are entirely impractical, such as the age of theuniverse. By contrast, quantum computers are much faster (1000s of timesfaster) and consequently pose a much greater threat.

FIG. 8B illustrates an example 850 of a quantum-secure blockchain 852which implements quantum key distribution (QKD) to protect against aquantum computing attack. In this example, blockchain users can verifyeach other's identities using QKD. This sends information using quantumparticles such as photons, which cannot be copied by an eavesdropperwithout destroying them. In this way, a sender and a receiver throughthe blockchain can be sure of each other's identity.

In the example of FIG. 8B, four users are present 854, 856, 858, and860. Each of pair of users may share a secret key 862 (i.e., a QKD)between themselves. Since there are four nodes in this example, sixpairs of nodes exists, and therefore six different secret keys 862 areused including QKD_(AB), QKD_(AC), QKD_(AD), QKD_(BC), QKD_(BD), andQKD_(CD). Each pair can create a QKD by sending information usingquantum particles such as photons, which cannot be copied by aneavesdropper without destroying them. In this way, a pair of users canbe sure of each other's identity.

The operation of the blockchain 852 is based on two procedures (i)creation of transactions, and (ii) construction of blocks that aggregatethe new transactions. New transactions may be created similar to atraditional blockchain network. Each transaction may contain informationabout a sender, a receiver, a time of creation, an amount (or value) tobe transferred, a list of reference transactions that justifies thesender has funds for the operation, and the like. This transactionrecord is then sent to all other nodes where it is entered into a poolof unconfirmed transactions. Here, two parties (i.e., a pair of usersfrom among 854-860) authenticate the transaction by providing theirshared secret key 862 (QKD). This quantum signature can be attached toevery transaction making it exceedingly difficult to tamper with. Eachnode checks their entries with respect to a local copy of the blockchain852 to verify that each transaction has sufficient funds. However, thetransactions are not yet confirmed.

Rather than perform a traditional mining process on the blocks, theblocks may be created in a decentralized manner using a broadcastprotocol. At a predetermined period of time (e.g., seconds, minutes,hours, etc.) the network may apply the broadcast protocol to anyunconfirmed transaction thereby to achieve a Byzantine agreement(consensus) regarding a correct version of the transaction. For example,each node may possess a private value (transaction data of thatparticular node). In a first round, nodes transmit their private valuesto each other. In subsequent rounds, nodes communicate the informationthey received in the previous round from other nodes. Here, honest nodesare able to create a complete set of transactions within a new block.This new block can be added to the blockchain 852. In one embodiment thefeatures and/or the actions described and/or depicted herein can occuron or with respect to the blockchain 852.

FIG. 9 illustrates an example system 900 that supports one or more ofthe example embodiments described and/or depicted herein. The system 900comprises a computer system/server 902, which is operational withnumerous other general purpose or special purpose computing systemenvironments or configurations. Examples of well-known computingsystems, environments, and/or configurations that may be suitable foruse with computer system/server 902 include, but are not limited to,personal computer systems, server computer systems, thin clients, thickclients, hand-held or laptop devices, multiprocessor systems,microprocessor-based systems, set top boxes, programmable consumerelectronics, network PCs, minicomputer systems, mainframe computersystems, and distributed cloud computing environments that include anyof the above systems or devices, and the like.

Computer system/server 902 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 902 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 9, computer system/server 902 in cloud computing node900 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 902 may include, but are notlimited to, one or more processors or processing units 904, a systemmemory 906, and a bus that couples various system components includingsystem memory 906 to processor 904.

The bus represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Computer system/server 902 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 902, and it includes both volatileand non-volatile media, removable and non-removable media. System memory906, in one embodiment, implements the flow diagrams of the otherfigures. The system memory 906 can include computer system readablemedia in the form of volatile memory, such as random-access memory (RAM)910 and/or cache memory 912. Computer system/server 902 may furtherinclude other removable/non-removable, volatile/non-volatile computersystem storage media. By way of example only, storage system 914 can beprovided for reading from and writing to a non-removable, non-volatilemagnetic media (not shown and typically called a “hard drive”). Althoughnot shown, a magnetic disk drive for reading from and writing to aremovable, non-volatile magnetic disk (e.g., a “floppy disk”), and anoptical disk drive for reading from or writing to a removable,non-volatile optical disk such as a CD-ROM, DVD-ROM or other opticalmedia can be provided. In such instances, each can be connected to thebus by one or more data media interfaces. As will be further depictedand described below, memory 906 may include at least one program producthaving a set (e.g., at least one) of program modules that are configuredto carry out the functions of various embodiments of the application.

Program/utility 916, having a set (at least one) of program modules 918,may be stored in memory 906 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 918 generally carry out the functionsand/or methodologies of various embodiments of the application asdescribed herein.

As will be appreciated by one skilled in the art, aspects of the presentapplication may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present application may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present application may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Computer system/server 902 may also communicate with one or moreexternal devices 920 such as a keyboard, a pointing device, a display922, etc.; one or more devices that enable a user to interact withcomputer system/server 902; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 902 to communicate withone or more other computing devices. Such communication can occur viaI/O interfaces 924. Still yet, computer system/server 902 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 926. As depicted, network adapter 926communicates with the other components of computer system/server 902 viaa bus. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 902. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

Although an exemplary embodiment of at least one of a system, method,and non-transitory computer readable medium has been illustrated in theaccompanied drawings and described in the foregoing detaileddescription, it will be understood that the application is not limitedto the embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions as set forth and defined by thefollowing claims. For example, the capabilities of the system of thevarious figures can be performed by one or more of the modules orcomponents described herein or in a distributed architecture and mayinclude a transmitter, receiver or pair of both. For example, all orpart of the functionality performed by the individual modules, may beperformed by one or more of these modules. Further, the functionalitydescribed herein may be performed at various times and in relation tovarious events, internal or external to the modules or components. Also,the information sent between various modules can be sent between themodules via at least one of: a data network, the Internet, a voicenetwork, an Internet Protocol network, a wireless device, a wired deviceand/or via plurality of protocols. Also, the messages sent or receivedby any of the modules may be sent or received directly and/or via one ormore of the other modules.

One skilled in the art will appreciate that a “system” could be embodiedas a personal computer, a server, a console, a personal digitalassistant (PDA), a cell phone, a tablet computing device, a smartphoneor any other suitable computing device, or combination of devices.Presenting the above-described functions as being performed by a“system” is not intended to limit the scope of the present applicationin any way but is intended to provide one example of many embodiments.Indeed, methods, systems and apparatuses disclosed herein may beimplemented in localized and distributed forms consistent with computingtechnology.

It should be noted that some of the system features described in thisspecification have been presented as modules, in order to moreparticularly emphasize their implementation independence. For example, amodule may be implemented as a hardware circuit comprising custom verylarge-scale integration (VLSI) circuits or gate arrays, off-the-shelfsemiconductors such as logic chips, transistors, or other discretecomponents. A module may also be implemented in programmable hardwaredevices such as field programmable gate arrays, programmable arraylogic, programmable logic devices, graphics processing units, or thelike.

A module may also be at least partially implemented in software forexecution by various types of processors. An identified unit ofexecutable code may, for instance, comprise one or more physical orlogical blocks of computer instructions that may, for instance, beorganized as an object, procedure, or function. Nevertheless, theexecutables of an identified module need not be physically locatedtogether but may comprise disparate instructions stored in differentlocations which, when joined logically together, comprise the module andachieve the stated purpose for the module. Further, modules may bestored on a computer-readable medium, which may be, for instance, a harddisk drive, flash device, random access memory (RAM), tape, or any othersuch medium used to store data.

Indeed, a module of executable code could be a single instruction, ormany instructions, and may even be distributed over several differentcode segments, among different programs, and across several memorydevices. Similarly, operational data may be identified and illustratedherein within modules and may be embodied in any suitable form andorganized within any suitable type of data structure. The operationaldata may be collected as a single data set or may be distributed overdifferent locations including over different storage devices, and mayexist, at least partially, merely as electronic signals on a system ornetwork.

It will be readily understood that the components of the application, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations.Thus, the detailed description of the embodiments is not intended tolimit the scope of the application as claimed but is merelyrepresentative of selected embodiments of the application.

One having ordinary skill in the art will readily understand that theabove may be practiced with steps in a different order, and/or withhardware elements in configurations that are different than those whichare disclosed. Therefore, although the application has been describedbased upon these preferred embodiments, it would be apparent to those ofskill in the art that certain modifications, variations, and alternativeconstructions would be apparent.

While preferred embodiments of the present application have beendescribed, it is to be understood that the embodiments described areillustrative only and the scope of the application is to be definedsolely by the appended claims when considered with a full range ofequivalents and modifications (e.g., protocols, hardware devices,software platforms etc.) thereto.

What is claimed is:
 1. A system, comprising: a blockchain network,comprising: an orderer peer, configured to: create and propagate asequence of new blocks; and one or more peripheral peers, coupled to theorderer peer, each configured to: calculate hashes for the sequence ofnew blocks; add the hashes to a merkle tree; determine the merkle treeis different than merkle trees from a majority of peripheral peers;determine that one or more blocks that correspond to the differentmerkle trees from the majority of peripheral peers are different fromthe sequence of new blocks, and in response: cease committing blocks tothe blockchain network.
 2. The system of claim 1, wherein each of theone or more peripheral peers determines the calculated hashes are notdifferent than hashes from the majority of peripheral peers, and inresponse: commits the sequence of new blocks to the blockchain network.3. The system of claim 2, wherein the majority of peripheral peerscomprises most of the peripheral peers in the blockchain network anddoes not include the peripheral peer that calculates the hashes of thesequence of new blocks.
 4. The system of claim 2, wherein the one ormore peripheral peers determines the merkle tree is different thanmerkle trees from a majority of peripheral peers comprises the one ormore peripheral peers further configured to: obtain a local root nodehash of the merkle tree; transfer the local root node hash to themajority of peripheral peers; receive root node hashes from the majorityof peripheral peers for their merkle trees; compare the local root nodehash to each of the received root node hashes; and identify one or morereceived root node hashes as being different from the local root nodehash.
 5. The system of claim 4, wherein one or more peripheral peersdetermines that no merkle tree that corresponds to the received merkletrees from the majority of peripheral peers is different from the localmerkle tree, and in response: determines that a peripheral peer thatprovided a miscompared root node hash is a malicious peripheral peer;and commits the sequence of new blocks to the blockchain network.
 6. Thesystem of claim 2, wherein the one or more peripheral peers determinesthat one or more blocks that correspond to the different merkle treesfrom the majority of peripheral peers are different from the sequence ofnew blocks comprises the one or more peripheral peers further configuredto: request sequences of blocks that correspond to the different merkletrees from the majority of peripheral peers; receive sequences of blocksin response to the request; compare the received sequences of blocks tothe sequence of new blocks; and determine that the orderer peer is amalicious peer in the blockchain network in response to one or morereceived sequences of blocks are different from the sequence of newblocks.
 7. The system of claim 2, wherein the received sequence ofblocks and the sequence of new blocks are all correctly signed by theorderer peer.
 8. A method, comprising: receiving, by each of one or moreperipheral peers of a blockchain network, a sequence of new blocks froman orderer peer; calculating hashes for the sequence of new blocks;adding the hashes to a merkle tree; determining the merkle tree isdifferent than merkle trees from a majority of peripheral peers;determining that one or more blocks that correspond to the differentmerkle trees from the majority of peripheral peers are different fromthe sequence of new blocks, and in response: ceasing committing blocksto the blockchain network.
 9. The method of claim 8, wherein in responseto each of the one or more peripheral peers determines the calculatedhashes are not different than hashes from the majority of peripheralpeers, the method further comprising: committing the sequence of newblocks to the blockchain network
 10. The method of claim 9, wherein themajority of peripheral peers comprises most of the peripheral peers inthe blockchain network and does not include the peripheral peer thatcalculates the hashes of the sequence of new blocks.
 11. The method ofclaim 9, wherein the one or more peripheral peers determining the merkletree is different than merkle trees from a majority of peripheral peerscomprising: obtaining, by the one or more peripheral peers, a local rootnode hash of the merkle tree; transferring the local root node hash tothe majority of peripheral peers; receiving root node hashes from themajority of peripheral peers for their merkle trees; comparing the localroot node hash to each of the received root node hashes; and identifyingone or more received root node hashes as being different from the localroot node hash.
 12. The method of claim 11, wherein in response to oneor more peripheral peers determines that no merkle tree that correspondsto the received merkle trees from the majority of peripheral peers isdifferent from the local merkle tree, the method further comprising:determining, by the one or more peripheral peers, that a peripheral peerthat provided a miscompared root node hash is a malicious peripheralpeer; and committing the sequence of new blocks to the blockchainnetwork.
 13. The method of claim 9, wherein the one or more peripheralpeers determining that one or more blocks that correspond to thedifferent merkle trees from the majority of peripheral peers aredifferent from the sequence of new blocks comprising: requesting, by theone or more peripheral peers, sequences of blocks that correspond to thedifferent merkle trees from the majority of peripheral peers; receivingsequences of blocks in response to the request; comparing the receivedsequences of blocks to the sequence of new blocks; and determining thatthe orderer peer is a malicious peer in the blockchain network inresponse to one or more received sequences of blocks are different fromthe sequence of new blocks.
 14. The method of claim 9, wherein thereceived sequence of blocks and the sequence of new blocks are allcorrectly signed by the orderer peer.
 15. A non-transitory computerreadable medium comprising instructions, that when read by a processor,cause the processor to perform: receiving, by each of one or moreperipheral peers of a blockchain network, a sequence of new blocks froman orderer peer; calculating hashes for the sequence of new blocks;adding the hashes to a merkle tree; determining the merkle tree isdifferent than merkle trees from a majority of peripheral peers;determining that one or more blocks that correspond to the differentmerkle trees from the majority of peripheral peers are different fromthe sequence of new blocks, and in response: ceasing committing blocksto the blockchain network.
 16. The non-transitory computer readablemedium of claim 15, wherein the majority of peripheral peers comprisesmost of the peripheral peers in the blockchain network and does notinclude the peripheral peer that calculates the hashes of the sequenceof new blocks, wherein in response to each of the one or more peripheralpeers determines the calculated hashes are not different than hashesfrom the majority of peripheral peers, the method further comprising:committing the sequence of new blocks to the blockchain network.
 17. Thenon-transitory computer readable medium of claim 16, wherein the one ormore peripheral peers determining the merkle tree is different thanmerkle trees from a majority of peripheral peers comprising: obtaining,by the one or more peripheral peers, a local root node hash of themerkle tree; transferring the local root node hash to the majority ofperipheral peers; receiving root node hashes from the majority ofperipheral peers for their merkle trees; comparing the local root nodehash to each of the received root node hashes; and identifying one ormore received root node hashes as being different from the local rootnode hash.
 18. The non-transitory computer readable medium of claim 17,wherein in response to one or more peripheral peers determines that nomerkle tree that corresponds to the received merkle trees from themajority of peripheral peers is different from the local merkle tree,the instructions cause the processor to further perform: determining, bythe one or more peripheral peers, that a peripheral peer that provided amiscompared root node hash is a malicious peripheral peer; andcommitting the sequence of new blocks to the blockchain network.
 19. Thenon-transitory computer readable medium of claim 16, wherein the one ormore peripheral peers determining that one or more blocks thatcorrespond to the different merkle trees from the majority of peripheralpeers are different from the sequence of new blocks comprising:requesting, by the one or more peripheral peers, sequences of blocksthat correspond to the different merkle trees from the majority ofperipheral peers; receiving sequences of blocks in response to therequest; comparing the received sequences of blocks to the sequence ofnew blocks; and determining that the orderer peer is a malicious peer inthe blockchain network in response to one or more received sequences ofblocks are different from the sequence of new blocks.
 20. Thenon-transitory computer readable medium of claim 16, wherein thereceived sequence of blocks and the sequence of new blocks are allcorrectly signed by the orderer peer.